Pump piston



v Aug. 19, 1930. H. w. MILLMINE 1,773,629

PUMP PI'sToN Filed sept. 2o, 1929 y Patented Aug. 19, `1930` HERBERT vv.iunlmszrnvns or Hous'roN, irExAs :PUMP PISTON Application led September20, 1929. Serial No. 393,861.

My invention relates topump pistons andmore particularly to pumpvpistons such as are used inslush pumps andgthe like in' well drillingor similar operations. It is adapted for use in single or' double actingpumps in which heavy pressures are sometimes necessary.

It is an object of my invention to provide a pump piston which will beof strong and sturdy construction adapted to work under heavy pressuresand which will make a close seal with'the' wall of the pump liner for along period of time.

I also desire to form a pump piston which is adapted to be expanded onthe advancingl end thereof thru the fluid pressures against which thepiston operates.

My pump piston is also adapted to be madev cheaply so that it can beused economically 2o in the artfand'is`so arranged that it may be easilyrepaired when desired.

It is also an object to provide a pump piston of the character whichismade and assembled in separate parts so that one art may be renewedwithout the necessity o renewing other parts of the pistoni Otherobjects closely relatedfy to those already enumerated will more clearlyappear in the detailed description which follows.

Referring to the drawing herewith, Fig. 1 is a entral longitudinalsection thru a piston pump employing'my-invention and taken on the line1-1 of Fig. 2. l

Fi 2 is a transversesection taken ap` f proximately on the plane 2-2 ofFig. l and fpart of this view being in section dfor greater-`clearn'ess. v Y

I contemplate providing a piston pump 1 the parts of which may beassembled directly 4C*` upon the piston rod, which is drawn inFig.

lat 3. Said piston 10d/may be of cylindrical formation, having thereonand spaced from y the enda ring or ange 4'serving as a stop memberagainst which the parts of the piston may bear. The outer end of thepiston rod is threaded to receive a nut 5` adapted to clamp a number ofthe packing discs or members upon the rod. The inner end of said nut 5and the flange 4 have tapered bearing faces 6 thereon to fit within atapered seat 7 in 11l which may be of iron or steel or even of toso-arrange the bosses so that regardless of each of the outer plates ofthe piston. This seat tends to center the plates or disc with respect tothe rod if they lit loosely.

. The piston body is made up of a plurality of Vconvexe-concave discsadapted to it together to make up a packing member to fit Within ,thepump cylinder. I have shown the each discs 8, at each end of the piston.These discs are of identical construction, and are shown as being.concaved or dished toward the ends to have a saucer like form. vAdjacent t-he two end discs are the two intermediate discs 9, Ysaiddiscs 9 being also convexo-concave and identical in construction.vBetween the'two intermediate discs 9 is a concaveconcave ring 10adapted to interfit with and support the two adjacent discs 9.

The discs 8 at each end of the piston arev made up of a rigid renforcingbody or plate hardrubber or other material adapted to maintain its shapeand resist the strain to which it is subjected. The late 11 is ofksmallervdiameter than the bo y ofthe piston and the forward and rearfaces of the plate are :formed withshort studs or bosses 12 thereonspaced upon the face of the disc or plate as vshown in Fig. 2. The outerends of the bosses may conform to the curvature of the plate or they maybe formed perpendicular to the axis of the disc for simpllcity inconstructing the dies@ 'l The bosses adjacent'vthe center of the plateare shown as larger than those towards the margin. These bosses orjstuds may be spaced apart in any desired configuration or arrangementbut preferably at a proper distance .to provide between them a space inwhich a rubber body 13 may be molded. -,It is also desired the positionin which two of the discs may be assembled there will always be severalofthe bosses which will come' in contact with the bosses of the nextplate'and serve to space the plate apart.

v As will be understood from Fi ure 1, the rubber portion 13 entirelysurroun s the plate 11 and extends beyond the peripheryn On` the outerside towards the end of the piston, j the rubber portion is 0f Suicientdepth toren/160 I with the rubber body. The' outer periphery of therubber forming the disc 8 is curved outwardly so as to be oversize andto form a lip 14 which may be compressed somewhat by the cylinder wallwhen the piston is in position. rllhis'lip 14is shown as formed with areverse curve at 20. In Ythis manner sufficient material is present toprovide a substantial body portion to withstand the high pressure of thepump. The idea of placing a reverse or ogee curve on the face of thepiston ring is old in the art and is illustrated in the expired patentto Luton No.l 289,776,

' issued December 14, 1883.-

The inner discs 9 are also convexo-concave with their end faces adaptedto lit against the plates or discs 8, the inner sides of thesediscsbeing convex asmay be seen in Figure 1. The plates 9 are providedwith projecting bosses 12 thereon as shown in Fig. 2 and around thesebosses the rubber packing member or body is molded, the rubber coming-lush with the ends of th'e bosses on theforward and rearward sides.Vrlheouter periphery of each of these plates is also surrounded by aliner or rubber of similar composition as shown at 15 which may or maynot be a por-7- tion ofthe rubber 13. i

Two pairs of discs 8 and 9 are placed upon the piston rod and faded inoppositev di'rections to form the piston and comprise the packingportion thereof. To assist in spacin the inner discs 9 apart and to takeup the end thrust due to the pumping pressures, l have placed a spacingring 10 of rigid material between the two discs 9. rlhis spacing ring isshown as formed to l[it the adjacent faces of the two discs 9 and ispreferably of smaller diameter than either ot the said discs. The outersurface of spacin spaced from the wall o the cylinder linei` so that noscoring of a liner-may take place. I do not contemplate placing anyrubber on this spacingring but its periphery might be cient diameter toengage the. cylinder liner.

In assembling my piston upon the piston rod 3 the separate saucers ordiscs are set in the position shown in Fig. 1 upon the rod., the innerplate abutting against the ring or lange 4. The nut 5 isscrewedinposition on the end oftheI rod and the forward end is received withinthe recess 7' in the ,outer plate-` 8 and willclamp the parts irmly inposition so that 'no relative movement of the separate discs may takeplace." A

l In operation the lips 14 or end of plates will be compressed slightlywhen the; piston is inserted' within the liner and there will be aresilient pressure 4ateach end of the piston bearing'againstthe cylinderand as the piston is reciprocated the 4advancing end of the piston willbe acted uponby'-ltheuid pressures ring is therefore.

developed 1n the pump and such pressure will L assist 1n moving the lips14 against the wall of the liner and will assure a tight seal betweenthe piston and liner at all times.

The advantages of my construction lie in the fact that the piston is ofstrong construction adapted to withstand heavy pressures in bothdirections because the flexible material is adequately reenforced andbonded to the metal; and also that the parts ymay be easily removed'andreplaced. If one portion of the piston is damaged only that portion ordisc need to be replaced and the'cost ,of the upkeep is materially lessthan in pistons where the whole piston head must be discarded when aportion becomes worn. It will be seen that there will be a metal ltometal Contact by means of the bosses between the plates making up mypiston throughout the `length of the piston and the strain upon therubber will be greatly the spacing ring 10 it seems obvious that forvarious purposes the pistonmay be assembled with two discs 9 and thespacer ring, or two discs 8 and the ring.I Also the spacing ring may bedispensed with and the discs backed together for a double acting piston.If a single acting piston is desired, one, two or more of the discs maybe used all facing in thesame direction. The essential feature of theinvention being the individual saucer or disc a plurality of which maybecombined orassembledas esired. c

Having described my invention'what I desire to secure by'Lctters Patentis 1. lA pump piston adapted to be secured l upon a piston rod includinga plurality of sets of plates of rigid material concaved toward theadjacent end'of the piston, and a f corn ssible material on said coveredif desired should it be made of suffi 'covermg o Pr@ .plates enclosinglthe periphery thereof to form a seal with the cylinder walls.-

2. A pump piston adapted tobe secured upon a piston rod including aplurality of sets of plates of rigid material at' each end of saidpiston, said plates being concaved toward the adjacent end of thepiston, and a covering of compressible materialon said' plates enclosingthe' periphery thereof to form a seal with the cylinder walls.

3. A. pumpfpiston adapted .to be secured upon a piston rod including aplurality of sets of plates of rigid material concaved 'toward. the'adjacent endv of the piston, said plates being formed with short studsthereon contacting with adjacent plates to take up end thrust on saidpiston, and a covering of compressible material on said plates enclosiing the periphery thereof to form a seal with the cylinder walls.

4. A pump piston adapted to be-secured upon a piston rod including a'plurality .of sets of plates of rigid material at eachend of saidpiston, said plates being concaved `toward the adjacent end of thepiston, said plates being formed with short studs thereon contactingwith adjacent plates to take up end thrust on said piston, anda coueringof compressible material onsaid plates enclosing the periphery thereofto form a seal with the cylinder walls.

5. A pump piston including a piston rod, platesat each end of thevpiston concaved `toward the adjacent end thereof, studs on rsaid platesadapted to contact with adjacent plates, a covering of rubber moldedabout said plates between said studs, and means to clamp said platesupon said rod.

6. A pump piston including a piston rod, plates at each end of thepiston concaved toward the adjacent end thereof, studs on said A form aseal therewith.

in said plate, and a plates adapted to contact with adjacent plates, acovering of rubber molded about said plates between said studs,longitudinally extending lips on the endmost of said plates and'means toclamp said plates upon said rod.

. 7. A piston includin'gend plates dished to present a concave facetoward the ends thereof, afspacing plate of smaller diameter betweensaid end plates, studs on said end plates and-a layer of rubber betweensaid studsand about the peripheries of said end plates to contact withthe cylinder walls and 8. yA piston including end plates dished topresent a concave face toward the ends thereof, a spacing plate ofsmaller diameter between said end plates, lstuds on said end plates anda layer of rubber between said studs and about the peripheries ofsaidend plates to contact with the cylinder Walls and form a seal therewithAand means to clam said plates rigidly to a piston rod.' f .l

9. A pum piston including in combinationa pluralltyof interlittingsaucer shaped a body of rubber molded about said plate and i HERBERT W.MILLMINE.

discs, and means'. to retain said discs'on the piston rod. l

l10. A pump piston made upof a plurality 4of saucer shaped discs, eachdisc including plate, and resilient materiali carried thereby."

a rigid reenforcing l11. An article`of manufacture comprising a'convexe-concave plate, a central opening plurality of outstandingbosses thereon. l

12. An article of manufacture comprising a convexo-concave plate, acentral opening in said plate, a plurality of outstanding bossesthereon, and a body of rubber molded about said bosses.

13. A dise adapted to form one element of a pump piston and including aplate of metal,

